From 90ac3dc85ea07cc8ac40d51a2b96da4693128d3b Mon Sep 17 00:00:00 2001 From: Rich Trott Date: Fri, 26 Nov 2021 00:58:39 -0800 Subject: [PATCH] doc: add information on suppressing initial break in debugger MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Closes: https://github.com/nodejs/node/issues/40857 PR-URL: https://github.com/nodejs/node/pull/40960 Reviewed-By: Antoine du Hamel Reviewed-By: Michaël Zasso Reviewed-By: James M Snell --- doc/api/debugger.md | 39 +++++++++++++++------------------------ 1 file changed, 15 insertions(+), 24 deletions(-) diff --git a/doc/api/debugger.md b/doc/api/debugger.md index c5e019e5412278..2bfb08771dffe4 100644 --- a/doc/api/debugger.md +++ b/doc/api/debugger.md @@ -6,8 +6,12 @@ -Node.js includes a command-line debugging utility. To use it, start Node.js -with the `inspect` argument followed by the path to the script to debug. +Node.js includes a command-line debugging utility. The Node.js debugger client +is not a full-featured debugger, but simple stepping and inspection are +possible. + +To use it, start Node.js with the `inspect` argument followed by the path to the +script to debug. ```console $ node inspect myscript.js @@ -25,15 +29,12 @@ Break on start in myscript.js:2 debug> ``` -The Node.js debugger client is not a full-featured debugger, but simple step and -inspection are possible. - -Inserting the statement `debugger;` into the source code of a script will -enable a breakpoint at that position in the code: - - +The debugger automatically breaks on the first executable line. To instead +run until the first breakpoint (specified by a [`debugger`][] statement), set +the `NODE_INSPECT_RESUME_ON_START` environment variable to `1`. -```js +```console +$ cat myscript.js // myscript.js global.x = 5; setTimeout(() => { @@ -41,24 +42,13 @@ setTimeout(() => { console.log('world'); }, 1000); console.log('hello'); -``` - -Once the debugger is run, a breakpoint will occur at line 3: - -```console -$ node inspect myscript.js -< Debugger listening on ws://127.0.0.1:9229/621111f9-ffcb-4e82-b718-48a145fa5db8 +$ NODE_INSPECT_RESUME_ON_START=1 node inspect myscript.js +< Debugger listening on ws://127.0.0.1:9229/f1ed133e-7876-495b-83ae-c32c6fc319c2 < For help, see: https://nodejs.org/en/docs/inspector < +connecting to 127.0.0.1:9229 ... ok < Debugger attached. < - ok -Break on start in myscript.js:2 - 1 // myscript.js -> 2 global.x = 5; - 3 setTimeout(() => { - 4 debugger; -debug> cont < hello < break in myscript.js:4 @@ -252,5 +242,6 @@ Chrome DevTools doesn't support debugging [worker threads][] yet. [ndb][] can be used to debug them. [Chrome DevTools Protocol]: https://chromedevtools.github.io/devtools-protocol/ +[`debugger`]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/debugger [ndb]: https://github.com/GoogleChromeLabs/ndb/ [worker threads]: worker_threads.md